labo

Question 1

what contains endo agar

Answer 1

• contains FUSCHSIN SULFITE (indicator that turns red in acid conditions) and LACTOSE which coliforms ferment to produce lactic acid
• non-lactose fermenter= colorless

Question 2

why incubation temperature of mFc is higher

Answer 2

to inhibit growth of pathogens that are not from fecal origin

Question 3

composition of RCAF + inhibits what

Answer 3

• FUROXONE selection and anaerobic medium inhibits growth of STAPHYLOCOCCI or MICROCOCCI
• • • Pink colonies = P. avidum (mucoid) or P. granulosum (dry)
  • Buff-colored colonies: P.acnes

Question 4

KEA inhibits what + composition

Answer 4

• kanamycin and azide inhibits growth of GRAM - and most of GRAM +
• esculin is split yielding a phenolic compund which binds with the iron present= black color

Question 5

EMB inhibits what

Answer 5

• eosin and methylene blue inhibit most microorganisms that are NOT GRAM - ENTERIC BACILLI

Question 6

S4 (single step selection for staphylococci

Answer 6

• 5% sodium chloride and potassium tellurite inhibit most GRAM + AND -
• S. aureus reduces tellurite to produce anthralites black colonies

Question 7

nessler’s reagent

Answer 7

Nessler’s reagent turns yellow/brown upon reactiong with ammonia